The linework was digitized in 1997 from a paper copy of the 1996 map at
the U.S. Geological Survey's Alaska Section (Geologic Division) facilities in
Anchorge, AK. The original Transverse Mercator projection of the map (Central
Meridian: 100*W; Scale factor: 0.926; Reference ellipsoid:(6371204m, 63712004m)) was
converted to an Albersequal-area coverage in ARC/INFO (version 7.1.2). The
resulting coverage did not align exactly with an Albers equal-area coverage of the
Alaskan coastline, so a rubber-sheeting operation was performed using points
along the coastline and major rivers to match an Albers equal area projection.
Map unit (polygon) locations and
attributes were checked by the person responsible for the digitizing, and spot-checked
by one reviewer reviewer, by comparing a printed copy of the coverage to the
published map. Metadata were collected using document.aml v. 7.1.1, distributed by ESRI, Inc.
None completed or planned.
MATURITY.DAT (see Entity_and Attribute_Information). The item "MATURITY" can
be used to establish relates.
Johnsson, M.J., and Howell, D.G., compilers, 1996, Generalized Thermal Maturity
of Alaska, U.S. Geological Survey Miscellaneous Investigations Map I-2494.
Johnsson, M.J., and Howell, D.G., Eds., 1996, Thermal Evolution of Sedimentary Basins
in Alaska-U.S. Geological Survey Bulletin 2142, U.S. Government Printing Office,
Washington, D.C., 131p.
Johnsson, M.J., Pawlewica, M.J., Harris, A.G., and Valin, Z.C., 1992, Vitrinite
reflectance and conodont color alteration index data from Alaska: Data to accompany
the Thermal Maturity Map of Alaska: U.S. Geological Survey Open File Report 92-409, 3
Macintosh-formatted 3 1/2" high density (1.44 Mb) diskettes.
The completeness and quality of the generalized maturity data in the digital
coverage is that of the published 1996 map, which itself summarized data released in
1992 and collected prior to that date (mainly since 1980). No recent data have been
added. The geographic accuracy of the published map has been slightly degraded by
the rubber-sheet operation.